...yeah I've got more and more to say with this topic. But one of the main things is this, your "internal rules" that help you make your decisions, you are going to learn that sometimes, they have to be broken, or even worse, there is no right choice. Nothing has bothered me more in my life then coming to a decision and realizing it's a 'Kobayashi Maru' (Star Trek reference). It's a no win situation. But here is the thing, you have to be able to look yourself in the mirror and live with yourself and your decisions. Very few times in my life have I ever been forced into a decision totally against my will. I've tried to not put myself in those situations. Now that's not to say, I haven't gotten in bad situations... But most of those were my own doing and I own that. I had to live with my decisions and I can also tell you, while I'm not perfect, there isn't a lot I regret in my life.
So in your life, learn to evaluate your situations and make the best decisions you can, because at the end of the day you might be able to go home and go to bed without having to look yourself in the mirror, but the next morning that reflection will be waiting. So set yourself up to smile at it and know you made the best decision you could in that situation, with the information you had, using your own code.